1. Field of the Invention
The present invention relates generally to control systems, and more particularly to control systems for photographic printers.
2. Description of the Prior Art
Control systems for photographic film printers are known. One such printer is described in U.S. Pat. No. 4,045,136, and utilizes digital control logic for controlling the operation of light valves in a photographic film printer. Information for controlling the operation of the control system is contained on paper tapes which are read into the control system by a tape reader. The tapes may take the form of a composite tape containing both color information and cuing information, or the system may read a tape having color information only, with the cuing information being obtained from an external source or from a second tape containing the cuing information. In such a system, the tape (or tapes) are continuously run through a tape reader (or readers) during the printing operation in order to control the operation of the printer.
While such a printer control system provides a way to control the operation of a photographic film printer automatically, the continuous reading of one or more tapes is disadvantageous since the physical presence of the tapes during the printing process in a nuisance, and containers for the tapes, some of which may be quite long, must be provided. The continuous reading of a tape results in rapid tape wearout, and the tape may be damaged by an inattentative operator. Moreover, the continuous reading of tapes can result in tape jams and more rapid wearout of the tape reader. Finally, two separate tape readers must be provided if a two tape reading capability is desired. Such separate readers increase the overall cost of the system.